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Surgery may be needed if medicine fails to heal a tear
(fissure) in the
anus. The preferred procedure is lateral internal
sphincterotomy. A doctor makes a small incision in the internal anal sphincter,
one of two muscles that control the anus. This can be done as outpatient
local anesthesia or
The internal anal
sphincter is always under tension, also known as resting pressure. If that
pressure becomes too high, a fissure may form or an existing one may not heal.
The incision reduces the resting pressure, allowing the fissure to heal.
It's important to understand that, even with surgery, an anal fissure
must heal on its own. A sphincterotomy involves operating on the sphincter
muscles, not closing the actual fissure.
Lateral internal sphincterotomy has a better success rate than any
medicine that is used to treat long-term anal fissures. The results last
longer, and fewer people have anal fissures come back after surgery than after
treatment with medicine.1
In some studies,
a greater number of people who had lateral internal sphincterotomy had some
inability to control gas or stool (incontinence)
after surgery compared to people treated with medicine. Despite these results,
satisfaction with this surgery is high. And a review of many studies showed
that the risk of incontinence was 8%. This means that about 8 out of 100 people
who had the surgery had some problem with incontinence. But this rate was not
very different from the rates seen in people who were treated with medicine for
their chronic anal fissures.2
study showed that lateral internal sphincterotomy was better than nitroglycerin
cream at healing chronic anal fissures. And there was no difference in
long-term continence between the people who used nitroglycerin cream and the
people who had surgery.3
If you are deciding
whether to have this surgery, it is important that you consider the chance of
incontinence. In some cases,
the risk of incontinence is too great to justify doing lateral internal
sphincterotomy. This may be true for women who develop a fissure while giving
birth, because they typically don't have a high resting pressure in their
internal sphincter. A procedure called anal advancement flap may be done
instead of sphincterotomy. In this procedure, the
edges of the fissure are removed, and healthy tissue is sewn over the
Nelson R (2007). Anal fissure (chronic), search date
January 2007. Online version of BMJ Clinical Evidence.
Also available online: http://www.clinicalevidence.com.
Nelson R (2006). Non-surgical therapy
for anal fissure. Cochrane Database of Systematic Reviews (4).
Brown CJ, et al. (2007). Lateral internal
sphincterotomy is superior to topical nitroglycerin for healing chronic anal
fissure and does not compromise long-term fecal continence: Six-year follow-up
of a multicenter, randomized, controlled trial. Diseases of the Colon and Rectum, 50(4): 442–448.
May 15, 2012
Anne C. Poinier, MD - Internal Medicine
& C. Dale Mercer, MD, FRCSC, FACS - General Surgery
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